Dan Cox is honestly more far-right than Doug Mastriano. He just never got as much national attention because he was not blowing a race that a normal R may have otherwise been able to win (and never really had a shot to actually win either). Also Wes Moore underperforming Biden at all against him is absolutely indicative of him not being a strong Presidential nominee pick if he were to ever run for President, which he probably will at some point.
He underperformed by one point. That says nothing.,
1 state to the North, Josh Shapiro overperformed by 14 points. Merely approximating Bidens 2020 performance should not be seen as the modal outcome for a race where a Dem runs against someone as crazy as Doug Mastriano or Dan Cox.